The field of the disclosure relates generally to gas turbine engines and, more particularly, to the extraction of air from a compressor of a gas turbine engine.
Gas turbine engines typically include a multistage axial flow high pressure compressor which supplies high pressure air to a combustor. The compressor includes multiple stages. Each stage is composed of a stationary component referred to as a stator and a rotational component, which adds work to the system referred to as a rotor. A portion of compressed interstage air may be extracted for turbine section cooling, airframe pressurization, anti-icing, and other uses. Because work is added to air as it flows through each stage of the compressor, typically from the high-speed rotation of numerous rotor blades, it is desirable to extract, or bleed, air from the compressor after a number of stages.
Small quantities of air can be extracted through bleed slot openings within compressor casing systems. Some known bleed slots include assemblies of two cantilevered cases joined together to create a segmented annular ring having multiple bleed slot openings. The joints between these two cases, however, create leak paths for airflow through the bleed slot openings, and thereby a loss in the pressure that can be recovered downstream in a bleed cavity. Additionally, the separate pieces of the known bleed slot assemblies are known to move with respect to one another during operation of the gas turbine engine, which typically sees high temperatures and pressures in a complex and active thermodynamic environment. Such movement creates additional leak paths and pressure loss into the bleed cavity, which is undesirable. Furthermore, the shape of some known bleed slots create dead zones along their lengths where air flows significantly more slowly through the bleed slots, thereby creating further undesirable pressure losses.